I have a Gear Vendor Overdrive on my sm420 and 4.56 rear end that is original to the truck, it gives me a final 3.55 ratio. I know where two Eaton rear ends are with 4.10's but have not closed the deals yet. I think a 4.10 would be a nice improvement, especially milage. Right now, I'm getting 14.6 mpg both times I checked.
Last edited by lumbersawyer; 10/29/2023 2:31 PM.
